Crispness is a desirable textural attribute of dry snack foods, and its loss due to the absorption of moisture from the air is a cause of product rejection by the consumer. Absorbed water decreases the crispness of dry snack foods by plasticizing and softening the starch/protein matrix. Therefore, it would be desirable to find a method to retard moisture uptake by these products, thereby maintaining a desirable crisp texture for a longer period of time and prolonging product shelf-life.
A method for reducing moisture transmission would also be useful with foods such as bakery products and dehydrated fruits, vegetables and meats, where it is desirable to lower the rate of moisture absorption; and foods such as fresh fruits, vegetables and meats, and frozen foods, where it is desirable to reduce moisture loss.
Foods made with sucrose fatty acid polyesters are known to the art. U.S. Pat. No. 3,600,186 to Mattson et al., issued Aug. 17, 1971, describes low-calorie food compositions produced by replacing at least a portion of the fat content of a conventional food with a sugar fatty acid polyester or sugar alcohol fatty acid polyester. The polyesters are said to be useful as a partial or total replacement for normal triglyceride fat in salad or cooking oils, or plastic shortenings for use in frying, cake making, bread making or the like. A plastic shortening is disclosed made with 50% sucrose octastearate. A deep fat frying oil is disclosed made from erythritol tetraester of olive oil fatty acid (ETOFA). Also disclosed is pan frying and deep fat frying of various foods in ETOFA: potato pieces, eggs, beefsteaks, breaded shrimp and breaded codfish steaks.
European Patent Application No. 0,236,288 of Bernhardt, published Sept. 9, 1987, discloses sucrose polyesters esterified with C.sub.8 to C.sub.22 fatty acids. The preferred fatty acid composition is said to be 9-12% palmitic, 42-53% stearic, 19-39% oleic, 2-17% linoleic, 0-2% linolenic, 0-2% arachidic, 0-10% behenic, and 0-2% erucic. The polyesters are disclosed as being useful in making frying oils, and foods fried in oils such as potato chips, corn chips, and other fried farinaceous snack foods.
U.S. Pat. No. 4,005,195 to Jandacek, issued Jan. 25, 1977, discloses liquid polyol fatty acid polyesters and anti-anal leakage agents used for the treatment of hypercholesterolemia. In Example IV a cooking fat is disclosed made with 50% liquid sucrose polyester and 50% cocoa butter; the sucrose polyester is an average 7.5 ester of sucrose and oleic acid.
U.S. Pat. No. 4,005,196 to Jandacek, issued Jan. 25, 1977, discloses a combination of liquid polyol polyesters, anti-anal leakage agents, and fat-soluble vitamins. Example VI discloses a cooking fat made with 70% sucrose octaoleate and 30% sucrose octastearate.
U.S. Pat. No. 4,034,083 to Mattson, issued July 5, 1977, discloses polyol fatty acid polyesters fortified with fat-soluble vitamins and used in food or pharmaceutical compositions for treating and/or preventing hypercholesterolemia. Cooking oils and plastic shortenings are specifically mentioned. In Example V, Mattson discloses a plastic shortening said to be suitable for use in frying and other types of cooking, the shortening containing 40% xylitol pentaoleate.
None of these references suggests that polyol fatty acid polyesters are more effective at reducing moisture transmission than triglycerides, and none suggests that particular fatty acid compositions are required for this benefit.
It is, therefore, an object of the present invention to provide a method for reducing the rate of moisture transmission into and out of foods.
It is a particular object of the present invention to provide a method for preserving the crispness of dry cereal and/or starch based snack foods.
It is a related object of the present invention to accomplish the above-mentioned objects by coating the foods with particular polyol fatty acid polyesters.
These and other objects of the invention will become evident from the disclosures herein.
All parts, percentages and ratios used herein are by weight unless otherwise indicated.